Speaking of Guy English, he’s got a good piece on the multitouch gestures for iPad app-switching in iOS 4.3:

This all sounds wonderful but I still think they’re a bad idea and shouldn’t ship enabled by default. The problem isn’t that they’re not handy (zing), rather that they break what I feel is one of the key wonders of iPad — it becomes the application that is running.

I’m with Guy here. There is a need for a faster way to switch between running apps, but this isn’t the right solution. If those become a system default, then apps are limited to three touches.

(And please, stop with the predictions that these gestures suggest future home-button-less iPads or iPhones. Try explaining to a normal person that they need to use five fingers to get back to the home screen. People love the home button.)